Liquid crystals are fascinating materials with
properties intermediate between those of solids and liquids. They are important
for technological applications such as display devices, and layered liquid
crystalline structures are relevant to biological research on lipid bilayers.
An outstanding question in liquid crystal research is how molecular structure
influences observed macroscopic behavior. While there are empirical rules
underlying this connection, there is limited fundamental understanding. Our
work attempts to improve our understanding with the use of numerical
simulations.
We are engaged in carrying out large-scale numerical
simulations of a variety of models of liquid crystals. The models we use are phenemological in
nature, i.e. they do not include atomic-level detail, but do include the
essential molecular features such as shape, electric multipole moments and the
relative strengths of attractive and repulsive intermolecular
interactions. By considering
phenemological as opposed to atomistic models, larger systems can be simulated.
We study a variety of physical phenomena including: flexoelectricity (the electrical
response of a liquid crystal to an orientational deformation), the formation of
chiral liquid crystal phases from achiral molecules, the mechanism underlying
molecular tilt in smectic phases, the properties of topological defects in
nematics, and the properties of confined nematics. Simulation techniques include molecular dynamics and Monte Carlo
algorithms. Visualization (as indicated in the accompanying animations)
provides important insights into the physical behavior.